1. Agbola T. (2004) “Readings in Urban and Regional Planning” Published by Macmillan Nigeria Limited, Ibadan, Oyo State, Nigeria.
2. Bekele G. W., and Jackson R. W. (2006). Theoretical Perspectives on Industry Clusters. Regional Research Institute, West Virginia University, Morgantown, WV.
3. Blakely E. J., and Leigh N. G. (2010). Planning Local Economic Development: Theory and Practice, Thousand Oaks, CA: Sage Publications.
4. Global methane emissions from landfills: New methodology and annual estimates 1980-1996